In recent years, various vehicle lamps that are effective for a reduction of power consumption and a reduction of heat generation have been proposed (see e.g., Japanese Unexamined Patent Documents; JP-A-2004-342574; JP-A-2004-241388; and JP-A-2004-111355). According to such configurations, a light source supporting column shaped into a circular or square column is provided on a center axis (optical axis) of a reflector whose reflecting surface is formed like an almost hemisphere and then a plurality of LEDs (semiconductor light emitting devices) as a light source are arranged on an outer peripheral surface of the light source supporting column.
However, in configurations such as the above in which the plurality of LEDs are arranged around the light source supporting column positioned on the center axis of the reflector, the LEDs, which also serve as heating elements, are arranged densely on the light source supporting column at a high density. Therefore, a sufficient heat radiation area cannot be secured around the LEDs, and there is a risk that a luminous efficiency of the LEDs is decreased or a life of the LEDs is shortened due to the excessive temperature rise.
Also, in the above Patent Documents, there is disclosed a reflector whose plural reflecting surfaces, each having different reflecting characteristics, are formed around the light source supporting column on which the LEDs are arranged. The plural reflecting surfaces shift positions in the circumferential direction, so that a plurality of light distribution patterns can be given by one lamp. However, light emitted from one LED is incident on plural reflecting surfaces having different light distribution patterns respectively, or a part of the light reflected by one reflecting surface is reflected again by other reflecting surfaces. As a result interference occurs between plural light distribution patterns. Thus, a problem has arisen that it is difficult to control respective light distribution patterns with high precision.